Generally speaking, the present invention pertains to a timing mechanism having a power drive means rotating first and second cam means and a double pole switch means opening and closing in response to a rotation of the cam means comprising coupling means coupling the power drive means to the cam means; first and second movable spring blades disposed in substantially parallel relation and having lengths which are substantially equal, first and second electrical contacts one each carried on each of the blades respectively near distal ends thereof and facing each other, a third spring blade fixedly disposed between the first and second spring blades and in substantial parallel relation therewith, the third spring blade having a length shorter than the lengths of the first and second spring blades so as to provide a gap between the same at their distal ends, and third and fourth electrical contacts carried on opposed surfaces of the third spring blade in operational position with the first and second electrical contacts; and first and second actuator arms pivotly mounted in ends thereof to be pivoted in response to the cam means, a distal end of one of the actuator arms entering the gap and engaging the first and second spring blades to open the first and second electrical contacts from said third and fourth electrical contacts, a distal end of the other actuator arm entering the gap and engaging one of the first and second spring blades to open one of said first and second electrical contacts from one of the third and fourth electrical contacts.
One of the cam means includes a sharp contour to a step with one of the actuator arms engaging the cam means to quickly drop at the sharp drop contour to the step. The timing mechanism also includes, in this embodiment, an audible sound means having a spring biased striker pivotly carried on the actuator arm and engaging the audible sound means, whereby the striker drops with the actuator arm and continues dropping after the arm engages the step to strike the audible sound means.
In another embodiment of the invention there is provided a short pulsing cycle within a complete program of the timing mechanism. In this embodiment one of the actuator arms serves to provide the short pulsing cycle and there is a manual selector means serving as a means to disengage the second actuator arm from its cam means to render the pulsing cycle inoperative for a predetermined period of time.
The present invention pertains to a timing mechanism and more particularly to a timing mechanism which provides a short pulsing cycle within a timing program and an alarm system to signal the end of a program and wherein a double pole switching means is also provided.
Timing mechanism have for sometime been used to control the functions of various appliances such as washers, dryers and microwave ovens. Depending upon the application, such timing mechanisms need to provide various programs. For example, in the case of a timing mechanism for a microwave oven there is a need to provide a short pulsing cycle operable within the overall program. Such a system usually requires a double pole switching arrangement and in most cases there should also be a means to remove the pulsing cycle from the system if desired. In addition, there is also sometimes a need to provide an alarm means in conjunction with the timing mechanism to signal the end of a program.